Simplify stop_machine
stop_machine creates a kthread which creates kernel threads. We can
create those threads directly and simplify things a little. Some care
must be taken with CPU hotunplug, which has special needs, but that code
seems more robust than it was in the past.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
diff --git a/include/linux/stop_machine.h b/include/linux/stop_machine.h
index 18af011..36c2c72 100644
--- a/include/linux/stop_machine.h
+++ b/include/linux/stop_machine.h
@@ -17,13 +17,12 @@
* @data: the data ptr for the @fn()
* @cpu: if @cpu == n, run @fn() on cpu n
* if @cpu == NR_CPUS, run @fn() on any cpu
- * if @cpu == ALL_CPUS, run @fn() first on the calling cpu, and then
- * concurrently on all the other cpus
+ * if @cpu == ALL_CPUS, run @fn() on every online CPU.
*
- * Description: This causes a thread to be scheduled on every other cpu,
- * each of which disables interrupts, and finally interrupts are disabled
- * on the current CPU. The result is that noone is holding a spinlock
- * or inside any other preempt-disabled region when @fn() runs.
+ * Description: This causes a thread to be scheduled on every cpu,
+ * each of which disables interrupts. The result is that noone is
+ * holding a spinlock or inside any other preempt-disabled region when
+ * @fn() runs.
*
* This can be thought of as a very heavy write lock, equivalent to
* grabbing every spinlock in the kernel. */
@@ -35,13 +34,10 @@
* @data: the data ptr for the @fn
* @cpu: the cpu to run @fn on (or any, if @cpu == NR_CPUS.
*
- * Description: This is a special version of the above, which returns the
- * thread which has run @fn(): kthread_stop will return the return value
- * of @fn(). Used by hotplug cpu.
+ * Description: This is a special version of the above, which assumes cpus
+ * won't come or go while it's being called. Used by hotplug cpu.
*/
-struct task_struct *__stop_machine_run(int (*fn)(void *), void *data,
- unsigned int cpu);
-
+int __stop_machine_run(int (*fn)(void *), void *data, unsigned int cpu);
#else
static inline int stop_machine_run(int (*fn)(void *), void *data,